This application claims priority of the German utility model application 201 11 599.9 filed Jul. 11, 2001 which is incorporated by reference herein.
The invention concerns a dispenser for thin knives, in particular for thin replaceable microtome knives.
Thin knives, in particular thin replaceable microtome knives, are used as so-called xe2x80x9cdisposable bladesxe2x80x9d for sectioning preparations with a microtome for subsequent microscopic examination. The replaceable microtome knives are received by special knife holders and clamped therein. For sectioning the preparation, the entire knife holder is received by a holding apparatus on the microtome.
The replaceable microtome knives have only a limited service life. As cutting performance declines, the knives must be replaced. The replaceable microtome knives are offered commercially in so-called xe2x80x9cdispensersxe2x80x9d; in these, several knives are arranged one above another in a housing and can be removed therefrom individually.
A dispenser of this kind for thin replaceable microtome knives is depicted and described, together with a knife holder, in DE 28 52 373 C2. The dispenser is characterized in that in a closed parallelepipedal housing, a stack of individual replaceable microtome blades arranged one above another is pressed by a leaf spring against the cover of the housing. Provided in the cover is a slider, with which one individual knife can be slid out through a slot arranged in the end wall of the parallelepipedal housing.
The knife can be slid directly into the knife holder by way of a stud shaped onto the dispenser and a corresponding blind hole in the knife holder. This requires, however, that the knife holder be accessible from the side. In addition, this dispenser can be placed only onto a special knife holder. If a special knife holder is not used, the blades must be removed by hand after being slid out of the knife holder, and inserted manually into the knife holder. Since the knife blade projects out of the dispenser in entirely unprotected fashion after being slid out, an increased risk of injury exists here.
It is therefore the object of the present invention to improve a dispenser of this kind for replaceable microtome knives in such a way that the risk of injury upon manual removal of the knife is minimized.
According to the present invention, this object is achieved by the characterizing features of claim 1. Advantageous developments are the subject matter of the dependent claims.
The invention is characterized in that the dispenser for thin replaceable microtome knives has, in one of the two longitudinal walls of the housing, an opening which is dimensioned in such a way that the knife is slid out of the housing along its longitudinal extension in a pivoting motion of the slider. In the process, the knife edge always faces in the direction of the opening, so that the knife is grasped at its non-hazardous narrow back surface and can be placed into a knife holder.
In an embodiment of the invention, provision is made for the back of the replaceable microtome knife to comprise at least one hole or at least one depression for a snap-in stud. It has proven advantageous, however, if the knife back comprises a continuous series of holes and/or depressions arranged next to one another. During manufacture of the knife, an xe2x80x9cendlessxe2x80x9d steel strip can be guided in planar fashion over a grinder in order to grind the knife edge, and can then be cut off to the desired knife length.
Provision is made for the slider to comprise a snap-in stud for engagement into the hole or depression on the knife. An actuation of the slider causes the knife to be slid out.
For more reliable handling, the slider is equipped with a recess that results in better finger contact with the slider.
In a further embodiment of the invention, the slider is guided in a groove in the cover of the housing, the groove being arranged obliquely with respect to the knife edge. The result of this is that one end of the knife is pivoted out of the housing and the other end of the knife remains in the housing. Provision can also be made for the slider groove to be arranged in the housing such that the slider engages the knife at a location spaced from the center of the knife such that one end of the knife is pivoted out of the housing and the other end of the knife remains in the housing.
In a further embodiment of the invention, the gap in the housing for pivoting the blade out has associated with it a support surface, located lower down, for the blade. This has the advantage that the blade is securely guided while being pivoted out, and moreover can be held securely against the support after being partially pivoted out.
Provision is furthermore made for the support surface to have associated with it a stop for limiting the movement of the knife that can be pivoted out. This prevents the knife from shifting unintentionally after being pivoted out, since on the one side it is guided by the slider and on the other side it rests on the support surface against a stop.